This invention relates generally to waterproof coating systems, and more particularly to a two-part water-based coating and method for applying the coating to a surface so that the coating is substantially immediately cured upon application to the surface.
Exterior coatings are exposed to the vicissitudes of weather from the very moment they are applied to protect an exterior surface. Water-based coatings are favored over solvent borne coatings for a number of well-known reasons. They offer ease of application, reduced toxic solvent emission, lower raw material and application costs, and easy cleanup of site and equipment. However, water-based coatings are particularly vulnerable to water damage during and immediately after application. A sudden summer shower can wash away or otherwise damage the result of many hours of labor and waste valuable materials.
Exterior water-based coatings may be formulated using aqueous dispersions of water-insoluble polymer latex as binders. After application, the aqueous carrier evaporates, and the individual latex particles coalesce to form an integral film. Some applications require relatively thick coating films, conventionally on the order of 20-40 mils (0.05-0.10 cm) or more. These coatings are often applied by spraying techniques with mixed results. Because they are applied as a thick coating, they lose water by evaporation relatively slowly in comparison with other polymer latex coating products such as house paints, which are typically applied at 5-8 mils (0.013-0.02 cm). Thus, roof coatings are particularly vulnerable to being washed off by unanticipated precipitation. In order to avoid roof coating washout or damage due to water, it is typically necessary to apply the full thickness in two or more separate applications, which effectively increases labor costs.
The application of such coatings also requires the laborer to haul heavy equipment and materials to the surface to be coated. This is especially inconvenient and time consuming when the coating is to be applied to a rooftop. Since some coating systems require components with high viscosity and large particle sizes, it would be very difficult to pump such liquids and particles to the rooftop from a lower level or over long lengths of tubing or hose.
Many roof membranes also require joint details or laps and mechanical or chemical fastening techniques that can eventually lead to membrane failure. In addition, commercial, industrial and home roof structures typically include many penetrations for vent stacks, mounting hardware for antennas or other equipment, and structures, with each penetration being a potential leak sight.
It would therefore be desirable to provide a coating system and method of application that overcomes at least some of the disadvantages of the prior art.